From 6398be7b28a2115f34db2ed23d810132bc46d1cc Mon Sep 17 00:00:00 2001
From: "Sharon (Sean) Rolel" <srolel9@gmail.com>
Date: Mon, 29 Jun 2020 07:14:32 -0400
Subject: [PATCH 1/2] treat modules with no extension as .js

---
 lib/internal/modules/esm/get_format.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/internal/modules/esm/get_format.js b/lib/internal/modules/esm/get_format.js
index 616b2cf52309ea..950bf0ad9b995a 100644
--- a/lib/internal/modules/esm/get_format.js
+++ b/lib/internal/modules/esm/get_format.js
@@ -50,7 +50,7 @@ function defaultGetFormat(url, context, defaultGetFormatUnused) {
   } else if (parsed.protocol === 'file:') {
     const ext = extname(parsed.pathname);
     let format;
-    if (ext === '.js') {
+    if (!ext || ext === '.js') {
       format = getPackageType(parsed.href) === 'module' ? 'module' : 'commonjs';
     } else {
       format = extensionFormatMap[ext];

From e3b12330615f7d0aeeab827937681d6a7db2eee7 Mon Sep 17 00:00:00 2001
From: "Sharon (Sean) Rolel" <srolel9@gmail.com>
Date: Thu, 2 Jul 2020 18:36:59 -0400
Subject: [PATCH 2/2] update tests

---
 test/es-module/test-esm-no-extension.js       | 34 +++++++++++++++++++
 ...nsion.js => test-esm-unknown-extension.js} |  6 ++--
 2 files changed, 36 insertions(+), 4 deletions(-)
 create mode 100644 test/es-module/test-esm-no-extension.js
 rename test/es-module/{test-esm-unknown-or-no-extension.js => test-esm-unknown-extension.js} (83%)

diff --git a/test/es-module/test-esm-no-extension.js b/test/es-module/test-esm-no-extension.js
new file mode 100644
index 00000000000000..12c004893c7f15
--- /dev/null
+++ b/test/es-module/test-esm-no-extension.js
@@ -0,0 +1,34 @@
+'use strict';
+
+const common = require('../common');
+const fixtures = require('../common/fixtures');
+const { spawn } = require('child_process');
+const assert = require('assert');
+
+// In a "type": "module" package scope, files with no extensions should
+// not throw; both when used as a main entry point and also when
+// referenced via `import`.
+
+[
+  '/es-modules/package-type-module/noext-esm',
+  '/es-modules/package-type-module/imports-noext.mjs',
+].forEach((fixturePath) => {
+  const entry = fixtures.path(fixturePath);
+  const child = spawn(process.execPath, [entry]);
+  let stdout = '';
+  let stderr = '';
+  child.stderr.setEncoding('utf8');
+  child.stdout.setEncoding('utf8');
+  child.stdout.on('data', (data) => {
+    stdout += data;
+  });
+  child.stderr.on('data', (data) => {
+    stderr += data;
+  });
+  child.on('close', common.mustCall((code, signal) => {
+    assert.strictEqual(code, 0);
+    assert.strictEqual(signal, null);
+    assert.strictEqual(stdout, 'executed\n');
+    assert.ok(stderr.indexOf('ERR_UNKNOWN_FILE_EXTENSION') === -1);
+  }));
+});
diff --git a/test/es-module/test-esm-unknown-or-no-extension.js b/test/es-module/test-esm-unknown-extension.js
similarity index 83%
rename from test/es-module/test-esm-unknown-or-no-extension.js
rename to test/es-module/test-esm-unknown-extension.js
index 3b1802a4dcedbd..efcf636369d608 100644
--- a/test/es-module/test-esm-unknown-or-no-extension.js
+++ b/test/es-module/test-esm-unknown-extension.js
@@ -5,13 +5,11 @@ const fixtures = require('../common/fixtures');
 const { spawn } = require('child_process');
 const assert = require('assert');
 
-// In a "type": "module" package scope, files with unknown extensions or no
-// extensions should throw; both when used as a main entry point and also when
+// In a "type": "module" package scope, files with unknown extensions
+// should throw; both when used as a main entry point and also when
 // referenced via `import`.
 
 [
-  '/es-modules/package-type-module/noext-esm',
-  '/es-modules/package-type-module/imports-noext.mjs',
   '/es-modules/package-type-module/extension.unknown',
   '/es-modules/package-type-module/imports-unknownext.mjs',
 ].forEach((fixturePath) => {